As disclosed in Japanese Patent Publication No. 22364/1983, a wheel for vehicles has a specific tread pattern specially designed to minimize the road noise of the tire. As disclosed in Japanese Patent Laid-Open Nos. 47606/1983 and 146603/1986, tires can be provided with members having specific values of physical properties to minimize noise. The members are included in the carcass layers and belt layers in the tire rubber.
The modifications of the tread pattern and of the construction of the carcass and belt layers made in the above described conventional wheels, adversely affect the steering stability and the ride of the vehicle, which are the essential performances required of a tire. Thus, it was possible, only to a very limited extent, to reduce the road noise of a tire through these measures without sacrificing performance of the tire.
One of the causes of road noise of a tire is due to the vibrations of the tread. The vibrations occur as the portion of the tire in contact with the road surface is turned to regain its original expanded state. The air in the air chamber resonates to generate a compressional wave having a specific frequency and a large amplitude.